One well-known type of envelope structure is a bangtail envelope. A bangtail envelope structure includes a flap or tail that is either removably attached to a closure flap of the envelope or a separate flap distinct from the closure flap of the envelope. In either case, the flap is designed so that it needs to be detached from the envelope in order to close the envelope with the closure flap. One application for such bangtail envelope structures is for return envelopes. Typically, return envelopes are used in a first mailed envelope for commercial activities such as the payment of bills, or the ordering of merchandise, or the like. For this type of use, the bangtail flap is generally sized to be larger than the closure flap, and can take the form of a return slip, coupon, or detachable order form, or it may simply be used as an advertising or promotion attachment to the return envelope. Upon receipt, the recipient can detach the bangtail flap and discard it, or use it as a part of the materials included in the return envelope.